31121232013 has 2 divisors, whose sum is σ = 31121232014. Its totient is φ = 31121232012.

The previous prime is 31121232007. The next prime is 31121232047. The reversal of 31121232013 is 31023212113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28955446569 + 2165785444 = 170163^2 + 46538^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31121232013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31121232073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15560616006 + 15560616007.

It is an arithmetic number, because the mean of its divisors is an integer number (15560616007).

Almost surely, 2^31121232013 is an apocalyptic number.

It is an amenable number.

31121232013 is a deficient number, since it is larger than the sum of its proper divisors (1).

31121232013 is an equidigital number, since it uses as much as digits as its factorization.

31121232013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 31121232013 its reverse (31023212113), we get a palindrome (62144444126).

The spelling of 31121232013 in words is "thirty-one billion, one hundred twenty-one million, two hundred thirty-two thousand, thirteen".